1. Field of the Invention
The present invention relates to an optical device having a zoom function that changes a focal length of a shooting optical system.
2. Description of the Related Art
As a zoom lens apparatus, there is known one that moves a zoom lens by a stepping motor. As a technology of the zoom lens apparatus, for example, there is Jpn. Pat. Appln KOKAI Publication No. 2006-65033. Jpn. Pat. Appln KOKAI Publication No. 2006-65033 discloses that a position of a zoom lens is detected by an analog position detection element and step-out of a stepping motor is detected during a moving operation of the zoom lens.